Re: getting "shell command argument contains a newline or carriage return:" error with pg_dumpall when db name have new line in double quote

On Mon, Feb 02, 2026 at 09:14:28AM -0500, Tom Lane wrote:
> =?utf-8?Q?=C3=81lvaro?= Herrera <alvherre@alvh.no-ip.org> writes:
>> This is not an objection to this patch, but I don't see why we should
>> allow newlines in tablespace names if we're going to restrict them in
>> names of roles and databases.  Is it only because pg_dumpall happens not
>> to dump a comment with the tablespace name on it, like we do for dbs and
>> roles?  Sounds unprincipled.
>> I think keeping these things under the same rules makes the most sense.
> 
> Yeah, I was thinking the same.

A while back, I did a bit of testing with a patch that disallowed line
feeds and carriage returns in all names by adding a check to namein,
namerecv, and namestrcpy.  I'm not sure exactly why I stopped, but that
seemed to work relatively well, although it is a quite large hammer.  I
also recall seeing this thread from 2016 [0], which I don't think has been
cited here.

In any case, even if this change goes through, we'll need to teach
applications like pg_dump to either 1) verify there are no names with \n\r
or 2) handle them appropriately for all supported server versions.  IMHO
(2) is quite fragile.

[0] https://postgr.es/m/flat/CAB7nPqRbDwmrZW-W6QW6AwiL1WoZJO4XJ-b1%2B_O4xyy67zn%3DFw%40mail.gmail.com

-- 
nathan